lead

Introduction

lead, metallic chemical element; symbol Pb [Lat. plumbum ]; at. no. 82; at. wt. 207.2; m.p. 327.502°C; b.p. about 1,740°C; sp. gr. 11.35 at 20°C; valence +2 or +4. One of the oldest metals used by humanity, lead was known to the ancient Egyptians and Babylonians. The Romans used it for pipes and in solder. It was one of the first metals mined in North America, where it was sought after especially for making shot.